|Type||Competed in Olympic Games|
|Born||22 May 1898 in Leeuwarden (NED)|
|Died||4 December 1977 in Amsterdam (NED)|
|Affiliations||Achilles, Arnhem (NED)|
Jansma, was one of eight members of the Achilles Krachtsportvereniging from Arnhem that represented the Netherlands in tug-of-war. The team had won the Dutch trials, and managed to earn a silver medal in Antwerp. This result was in doubt for some time, as the Official Results listed both the Netherlands and the US as winning second place. This confusion was ended in 1968, when Henk Janssen presented his silver medal and associated Olympic diploma.
|Games||Discipline (Sport) / Event||NOC / Team||Pos||Medal||As|
|1920 Summer Olympics||Tug-Of-War||NED||Sijtse Jansma|
|Tug-Of-War, Men (Olympic)||Netherlands||2||Silver|